A trench gate IGBT has been widely used as an IGBT with low on-resistance, and an injection-enhanced (IE) IGBT in which an active cell region connected to an emitter electrode and an inactive cell region including a floating region are alternately arranged in a cell formation region, thereby enabling the use of injection enhancement (IE) effect, has been developed. The IE effect is to increase the concentration of charge stored in a drift region by making it difficult to discharge holes from an emitter electrode side when the IGBT is in an on-state.
Japanese Patent Application Laid-Open Publication No. 2012-256839 (Patent Document 1) discloses a technique relating to an IE trench gate IGBT in which each linear unit cell region provided in a cell formation region includes a linear active cell region and linear inactive cell regions provided to sandwich the linear active cell region from both sides thereof.
Japanese Patent Application Laid-Open Publication No. 2013-140885 (Patent Document 2) discloses a technique relating to an IE trench gate IGBT in which each linear unit cell region provided in a cell formation region includes first and second linear unit cell regions, the first linear unit cell region includes a linear active cell region, and the second linear unit cell region includes a linear hole collector cell region.
Japanese Patent Application Laid-Open Publication No. 2006-210547 (Patent Document 3) discloses a technique relating to an insulated gate semiconductor device including a second semiconductor layer of a second conductivity type provided on a first semiconductor layer of a first conductivity type, a plurality of stripe-shaped trenches formed on a surface of the second semiconductor layer, and a plurality of third semiconductor regions of the first conductivity type selectively formed in a longitudinal direction between the trenches.